Phonographic apparatus



; A. 'c. BLANEY PHONOGRAPHIC APPARATUS Oct. 12,: 1937.

Filed April 30, 1935 lNVENTOP 7 Arthur C.Blaney BY v fiTTOR/VEY PatentedOct. 12, 1937 PHONOGRAPHIC APP RATUS Arthur C. Blaney, Collingswood, N.J., assignor 'to Radio Corporation of America, a corporation of DelawareApplication April 30, 1935, Serial n iaocs 14 Claims. (cl. 179-4003)This invention relates to phonographic apparatus, and more particularlyto sound recording and reproducing apparatus of the type employing V aphotographic disc whereon the sound is recorded in the form of anuninterrupted spiral,

the present invention being an improvement upon that disclosed andclaimed in the co -pendingapplication of Ellsworth D. Cook, Serial No.704,- Q05, assigned to the Radio 'Cor'poration of America.

In said co-pending application, there is dis closed a phonographemploying a record on which the sound is recordedin the form of anArchimedean spiral track, a stationary light source and associatedoptical system focusing a fine line of light radially across the recordso as to include all the spirals or sound track turns across one radius.On the other side of the record, a stationary photoelectric cell isdisposed, the active 7 element of the fcell having a length equal to thelength of the radial light line and being in alignment therewith; Inorder to mask off all the light except that desired at the reproducingpoint, an opaque mask provided with an Archimedean, transparent spiralis placed adjacent the record so that the spiral record track and thespiral in the mask will have the'same geometrical center. Since the rateof radius change of an Archij medean spiral is constant'throughout itslength, it is possible, by choosing a scanning spiral of proper pitchand rotating itv at a suitable speed relative to that of the record, tocause the two spirals to intersect, each other along the aforesaidradial light line, whereby only that portion of record spiral which isin alignment with both the scanning spiral and the light line at anyinstant will serve to affect the light passing to the photoelectric cellat that instant.

While a system using a scanning mask of. the foregoing type workssatisfactorily, it leaves open several sources of noise generation whichmight be serious enough, at times, to interfere with the properreproduction of sound. In the first place, since successive transverseportions -of the entire length of the scanning spiral are made use ofduring the reproduction of a record and since,

even despite the exercise of great care in forming the scanning spiral,it is hardly possible to form a spiral having absolutely uniform width.

throughout itslength, it is obvious that variations in its width alongits length will result in a'fmodulation of the reproducing beam notintendedpby the rec ord. Similarly, in the case of a scanningspiral-formed on a photographic disc or platc, if dust or "other,foreign matter should accumulate on the transparent'scanning spiral, thereproducing beam will be unintentionally modulated. Now, if thismodulation takes place at a frequency within the audible range, it isobvious that unrecorded and undesirablenoises due entirely to variationsin width of or foreign matter upon the scanning spiral will result.

According to another well known form of phonograph of the photographicdisc type, the scanning element is in the form of a disc or plate havinga small aperture therein and forming a part of an optical housing whichis moved radially across the record. Such a system is shown, forexample, in the patent to Dirzuweit, No. 865,- 574. With a system ofthis sort, however, relatively complicated machinery is necessary to actuate not only the scanning element, but also the optical system, thelight source, and the housing and supporting structure therefor.Moreover, a

system of this sort needs continual resetting and adjustment before itcan be used again once a record hasrbeen played. I The. primary objectof my invention is to provide improved photo-phonographic apparatus ofthe disc type which will be free from the foregoing difficulties.

More specifically, it tion to provide improved photo-phonographicapparatus of the disc type from which reproducis an object of my inveninphoto-phonographic apparatus of the" type specified, an improvedscanning device which will be free from sources of undesirable noisegeneration.-

A further object of'm'y inventionis to provide an improved scanningdevice as aforesaid by means of whichany desired number of repetitionsof a photographic disc record can be automatically obtained once theapparatus is set in opera tion. It is another object of my invention toprovide improved. photo-phonographic apparatus of the disc type fromwhich reproduction of a subsequent record may be had immediately uponthe completion of playing 'of a previous one without the necessity ofresetting any of the parts other than the replacing of the played recordby a new one. r r

Still another object of my invention is to provide, inphoto-phonographic apparatus of the type aforesaid, improved scanningmeans whereby a plurality of recordings upon a single disc may be eithersuccessively, simultaneously or alternately reproduced.

A further object of my invention is to provide improved record scanningmeans for photographic disc records by means of which a predeterminedtime interval between successive reproductions may be arranged.

A still further object of my invention is to provide, inphoto-phonographic apparatus of the type specified, improved scanningmeans which is simple in construction, inexpensive of manufacture, andhighly efficient in use.

The novel features of my invention are set forth with particularity inthe appended claims. The invention itself, however, both as to itsorganization and method of operation, together with additional objectsand advantages thereof, will best be understood from the following description of a specific embodiment thereof, when taken in connectionwith the accompanying drawing, in which Figure 1' is a side elevation ofone form of my invention, Y

Figure 2 is a iew taken on the line 22 of Figure 1, and I Figure 3is aview. taken on the line 33 of Figure 1.

7 Referring more specifically to, the drawing, wherein like referencecharacters designate corresponding parts throughout, there is shown amotor plate I on which is supported a motor 3 which drives a turntablesupporting spindle 5,

. the turntable I being made of a transparent material and supportinga'photographic record 9 having a 'spiral'sound track thereon. The upperend of the spindle 5 may be threaded, if desired, for the reception of anut I I which, in cooperation with a friction disc I3, serves tosecurely clamp the record 9 on the turntable "I.

Fixed to the'spindle 5 is a gear I5 which meshes with and drives a gear"I1 fixed to a stub shaft I9 adjacent the spindle 5. The shaft I 9 has aworm 2I formed thereon forv driving a gear 23 on a shaft 25 toYwhich isfixed a bevel gear 21, in turn driving bevel gear 29 on a shaft 3 I at aspeed greatly reduced from that of the spindle 5 for a purpose whichwill appear, presently. The shaft 3| is carried by abracket member 33and has fixed thereto a; sprocket 35. Also carried by the bracket 33 isa second shaft 31 which has a sprocket 39 fixed thereto, an endlessopaque scanning belt 4I having a number of scanning sections orapertures 43 formed therein at spaced points being trained around anddriven by the sprockets 35 and 39. If desired, the sprockets 35 and 39may be replaced by ordinary friction rollers, but I preferably usesprockets in order to prevent slippage of the belt 4| relative to therecord 9.

The sprockets 35 and39 are arranged to move the belt radially across therecord 9 under the turntable I, as clearly shown in Figure 1, the speedof the belt driving sprocket 35 being such that it will advance the belt4| at the same rate as that at which the spiral sound track movesradially inwardly as the record 9 rotates. It is for this reason thatthe shaft 3 I must be rotated at a much slower speed than the spindle 5.A fixed. optical system within "a casing 45. is suitably arranged toform a fine line of light radially across the record in alignment with(that is, in the same vertical plane with) the apertures 43. As the beltM is advanced by the sprocket 35, one of'its apertures 43 will serve, toscan the spiral record soundtrack along its length and the modulate'gllight passing through both the sound track and the active scanningaperture 43 at any particular instant will serve to affect aphotoelectric cell 41 preferably mounted on an upturned portion 49 ofthe bracket or mounting member 33 within the belt 4| and having anactive element at least as long as the radial light line on the record.Since the area of the active aperture 43 which may be operating at anytime is always constant and since it moves very, very slowly, it isobvious that no modulation of the light beam will be produced therebyand hence noundesirable noises will be generated on account of it.

The bracket member 33 is preferably split as at 34 and formed with acentral slot through which the screws 49 extend for adjustably securingit to the motor plate I, so that it may be adjusted radially of therecord in order to apply adequate tension to the belt 4! and tofacilitate bringing the apertures 43 into proper scanning relation withthe record. For a record having but a single spiral sound track, theapertures 43 should be spaced a distance just slightly greater than thegreatest radial distance across the sound track spirals, so thatrepetition of the selection will be automatically obtained by the nextsucceeding aperture becoming active as soon as the preceding one hasbecome inactive. By spacing the apertures 43 a greater distance apart, apredetermined time interval may be arranged between successive playings.Where a record is employed having two or more concentric spiral tracksthereon, the apertures 43 may be so arranged that first one and thenanother selection may be played, or so that all may be played simul:taneously or alternately, as desired. The particular spacing of theapertures may be made to suit any occasion or set of conditions, thusmaking my improved phonograph very useful in many fields such as radiobroadcasting, advertising, etc.

Although I have shown and described but one form of my invention, itwill be obvious to those skilled in the art that many othermodifications thereof are possible. For example, if found desirable,both sprockets 35 and 39 may be directly driven from the shaft 25without making the bracket 33 adjustable as described. The belt 4I maybe made of metal, leather, or any other suitable material and theapertures 43 may be cut out, stamped or otherwise formed therein, or thebelt 4| may be photographically formed to provide transparent sections4| therein. In any event, I desire that my invention shall not belimited except insofar as is necessitated by the prior art and by thespirit of the appended claims.

I claim as my invention:

1. In photo-phonographic apparatus, the combination of a rotatablerecord having a spiral sound track thereon, and a scanning elementcomprising an opaque endless belt associated with said record and havingat least one transparent scanning section therein, said belt beingarranged to move radially across said record whereby to cause saidsection to scan said sound track.

2. In photo-phonographic apparatus, the combination of a rotatablerecord having a spiral sound track thereon, a scanning elementcomprising an opaque endless belt associated with said record and havingat least one scanning aperture therein, said belt being arranged to moveand carry said aperture radially across said record whereby to scan saidsound track, and stationary means for supplying a fixed line of lightradially across said sound track in alignment with the path of movementof said aperture.

3. In photo-phonographic apparatus, the combination of a rotatablerecord having a spiral sound track thereon, a scanning member associatedwith said record and movable radially thereacross, said scanning membercomprising an opaque endless belt having a plurality of scanningapertures therein, andstationary means for supplying a fixed line oflight across said sound track, said scanning member and said stationarymeans being so arranged relative to the record that said scanningapertures and said light line all lie in a common plane.

4. The invention set forth in claim 3 characterized in that saidscanning apertures are spaced apart a distance at least as great as thegreatest radial distance across the spiral sound track.

5. The invention set forth in claim 3 characterized in that saidscanning apertures are spaced apart a distance such that a predeterminedtime interval will elapse between successive reproductions of therecord.

6. In photo-phonographic apparatus, the combination of a rotatablerecord having a plurality of concentric spiral sound tracks thereon, anda scanning member associated with said record and movable radiallyacross each of said spiral sound tracks, said scanning member'comprising an opaque member having a plurality of scanning sectionstherein so spaced apart that each of said sound tracks has at least onescanning section associated therewith for scanning the respective soundtracks as said scanning member moves radially thereacross.

8. The invention set forth in claim I characterized in that saidscanning apertures are further so spaced apart that each of said soundtracks will be reproduced successively.

9.,The invention set forth in claim '7 characterized inthat saidscanning apertures are further so spaced apart that each of said soundtracks will be reproduced alternately.

10. The invention set forth in claim 7 characterized in that saidscanning apertures are further so spaced apart that all of said soundtracks will be reproduced simultaneously.

11. In photo-phonographic apparatus, the combination of a record havinga spiral sound track thereon, a, scanning member comprising an endlessopaque belt having a scanning section therein, a pair of rollers aroundwhich said belt is trained for movement radially across said rec- 'ord,andrneans coupling said motor to said record and to at least one of saidrollers whereby to provide driving connection therebetween.

12. The invention set forth in claim 11 characterized by the addition ofmeans for preventing the slipping of said belt on said rollers relativeto said record.

13L Inphono-photographic apparatus, the combination of a record having aspiral sound track thereon, a scanning member comprising an endlessopaque belt having a scanning section therein, a mounting member, a pairof rollers supported by said mounting member and around which said beltis trained for movement radially across said record, means whereby saidmounting member is adjustable radially of said record, and meanscoupling said motor to said record and to at least one of said rollerswhereby to provide driving connection therebetween.

14. In photo-phonographic apparatus, a scanning device for scanning aspiral sound track, said device comprising an endless member having aplurality of scanning apertures therein adapted to cooperate with saidsound track.

ARTHUR o. BLANEY.

